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Is that Sufficient? – Plausibility, Expert Witness Testimony and Hindsight

SUFFICIENCY

In a recent article on this website we examined the case of Actavis vs Lilly and the
“plausibility” test for sufficiency of disclosure used in that case. We noted that
that this was a departure from the test for sufficiency that has been used previously
and that this case is likely to be appealed. A recent decision that uses a more usual
test for sufficiency, and which does not refer to Actavis vs Lilly, has now been
published – Regeneron vs Kymab ([2016] EWHC 87 (Pat)). In this article, we consider
the differing effects of these two approaches to sufficiency.

In a recent article on this website we examined the case of Actavis vs Lilly and the “plausibility”
test for sufficiency of disclosure used in that case. We noted that that this was a departure from
the test for sufficiency that has been used previously and that this case is likely to be appealed.
A recent decision that uses a more usual test for sufficiency, and which does not refer to Actavis vs
Lilly, has now been published – Regeneron vs Kymab. In this article, we consider the differing effects
of these two approaches to sufficiency.

The usual principle of sufficiency of disclosure is that the whole subject matter defined in the
claims must be capable of being performed without undue burden and without invention. In contrast,
Actavis vs Lilly marked a departure from well-known test for sufficiency in that it was held that
a patent was sufficiently disclosed if the skilled person would have considered the claimed invention
to be plausible in the light of the patent specification and the state-of-the-art.

The decision in the case of Regeneron vs Kymab has now been published. This case follows the more
usual principle of sufficiency and does not refer to the new test set out in Actavis vs Lilly.

To, perhaps, over-précis the complex subject matter of Regeneron vs Kymab, the patent relates to
the addition of human genomic sequences to mice and the and concomitant removal of mouse genomic
sequences.

As for Actavis vs Lilly, the mechanism used in Regeneron’s patent for achieving the technical result
is given and apparently operates in the manner disclosed. However, Regeneron’s patent was held not to
be sufficient over the whole scope of the claimed subject matter. This was because no one at the filing
date had achieved the large insertions and deletions claimed in the patent and, indeed, to date no one has
achieved these large insertions and deletions. This was convincingly demonstrated through the testimony
of expert witnesses.

Thus Regeneron vs Kymab stands in contrast to Actavis vs Lilly. In Actavis vs Lilly the mechanism of
action of the claimed pharmaceutical was known. Consequently, the claimed subject matter was held to
be plausible to the skilled person at the filing date. In this case, also, expert witness testimony
was important in the court’s decision. However, in contrast to Regeneron vs Kymab, in Actavis vs
Lilly data produced after filing successfully demonstrated the efficacy and mode of action of the
medicine of the medicine and thus supported the court’s decision that the patent was sufficient at
the filing date.

Thus we have two contrasting situations: (i) where it appears that sufficiency is plausible at the
filing date if the disclosure is later demonstrated to be correct and (ii) where a patent is
insufficient at the filing date if the disclosure is later found to be wanting. On the face of it,
the distinction appears to be evidence that is only available in hindsight.

The requirement that a patent be sufficient exists in order to prevent filing and granting of
speculative patents. However, in the cases of Lilly’s and Regeneron’s patents it looks very much
as if each of these cases was filed speculatively but the “speculative” subject matter of Lilly’s
patent was demonstrated to be correct and therefore was plausibly sufficient whereas the “speculative”
subject matter of Regeneron’s patent could not be demonstrated and therefore was insufficient at
the filing date.

Thus, we observe that if speculation means that the skilled person “thinks it could work” then
speculation is arguably allowed for patents that are eventually shown to work. Thus, following
the test of Actavis vs Lilly does not provide any disincentive against filing speculative patent
applications at all.

We might also note that placing implausible/impossible technical disclosures on file with patent
offices has a corrosive effect during the prosecution of other patent applications. This is
because these incorrect ‘technical’ disclosures will be taken to be prima facie correct during
examination of legitimate patent applications thus increasing their cost of prosecution and,
potentially, damaging their value and prospects for grant.

As noted at the head of this article, the decision in Actavis vs Lilly is likely to be appealed
and thus the requirements for sufficiency of UK patents are likely to be authoritatively
considered again. Regeneron vs Kymab illustrates that the approach employed in Actavis vs
Lilly is unusual and that a higher court might return to a more conventional test for sufficiency.